EP3118596A1 - Système et procédés pour capteurs de pression de jonction de tunnel magnétique - Google Patents
Système et procédés pour capteurs de pression de jonction de tunnel magnétique Download PDFInfo
- Publication number
- EP3118596A1 EP3118596A1 EP16178512.6A EP16178512A EP3118596A1 EP 3118596 A1 EP3118596 A1 EP 3118596A1 EP 16178512 A EP16178512 A EP 16178512A EP 3118596 A1 EP3118596 A1 EP 3118596A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer structure
- free layer
- pressure
- magnetization
- magnetic tunnel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 230000004888 barrier function Effects 0.000 claims abstract description 19
- 239000010410 layer Substances 0.000 claims description 218
- 230000005415 magnetization Effects 0.000 claims description 66
- 230000008878 coupling Effects 0.000 claims description 11
- 238000010168 coupling process Methods 0.000 claims description 11
- 238000005859 coupling reaction Methods 0.000 claims description 11
- 239000011229 interlayer Substances 0.000 claims description 9
- 238000002161 passivation Methods 0.000 claims description 5
- 239000000463 material Substances 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- 230000005641 tunneling Effects 0.000 description 5
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910017107 AlOx Inorganic materials 0.000 description 1
- 229910001017 Alperm Inorganic materials 0.000 description 1
- 229910003321 CoFe Inorganic materials 0.000 description 1
- 229910015372 FeAl Inorganic materials 0.000 description 1
- 229910015136 FeMn Inorganic materials 0.000 description 1
- -1 IrMn Inorganic materials 0.000 description 1
- 229910003289 NiMn Inorganic materials 0.000 description 1
- 229910019041 PtMn Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005328 electron beam physical vapour deposition Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000001755 magnetron sputter deposition Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001451 molecular beam epitaxy Methods 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000004549 pulsed laser deposition Methods 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/12—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress
- G01L1/125—Measuring force or stress, in general by measuring variations in the magnetic properties of materials resulting from the application of stress by using magnetostrictive means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/16—Measuring force or stress, in general using properties of piezoelectric devices
Definitions
- pressure sensors are used to determine the pressure within an environment.
- pressure sensors may be used to determine the pressure inside or outside of an airplane among other possible implementations.
- the pressure is measured with piezo-resistive sensors, where the resistance changes due to pressure applied to a surface.
- a pressure sensor device comprises a magnetic tunnel junction comprising a free layer structure, a tunnel barrier, and a reference layer structure, wherein one or more surfaces of the free layer structure is exposed to respond to a pressure medium; and a voltage source coupled to the magnetic tunnel junction, the voltage source providing electrical power to the free layer structure and the reference layer structure.
- the device further comprises a current detector coupled between the magnetic tunnel junction and the voltage source; and a pressure calculating device, configured to calculate a pressure based on a current detected by the current detector.
- an MTJ structure for sensing pressure may include a magneto-strictive free layer, a reference layer, and a tunnel barrier that separates the free layer from the reference layer.
- the free layer may have a surface affected by pressure in a medium.
- the medium may cause either tensile or compressive pressure to be applied to the free layer.
- the magnetization in this free layer may respond to pressure by changing the axis of magnetization, including the average magnetization direction, while the axis of magnetization for the reference layer is set to a reference direction.
- the resistance to electrical currents of the MTJ also changes. Based on the resistance to electrical currents of the MTJ, a current passing through the MTJ can be monitored to determine the pressure on the free layer.
- Figure 1 is a block diagram illustrating a pressure sensing system 100 that uses an MTJ 101 to directly sense the pressure in a medium 112.
- the MTJ 101 includes three layers, a free layer structure 102, intermediate tunneling layers 104, and a reference layer structure 106.
- the free layer structure 102 and the reference layer structure 106 are made of magnetic materials that have a specific axis of magnetization.
- the axis of magnetization for the free layer structure 102 changes in response to pressure caused by a pressure medium 112.
- the axis of magnetization of the free layer structure 102 may change in response to both tensile and compressive forces exerted by the pressure medium 112.
- the pressure medium 112 may be any object that exerts a force on the free layer structure 102.
- the pressure medium 112 may be a fluid having a pressure ranging from greater than to less than 1 atmosphere.
- the reference layer structure 106 has an axis of magnetization that is pinned to a particular orientation. That is, the axis of magnetization for the reference layer structure 106 does not change in response to pressure.
- In between the free layer structure 102 and the reference layer structure 106 is one or more intermediate layers 104. There may be a single tunnel barrier or a series of different layers between the free layer structure 102 and the reference layer structure 106.
- the free layer structure 102 is connected to an electrode 108 that receives an electrical current from a power source 118, such as a voltage source.
- the power source 118 is coupled to the free layer 108 through electrode 108 and provides power to the free layer structure 102 of the MTJ 101.
- the electrode 108 is coupled in such a way that the electrode 108 and any wiring or circuitry does not interfere with the pressure medium 112 becoming incident on a surface of the free layer structure 102.
- the electrode 108 may be on a surface of the free layer structure 102 that is not in contact with the intermediate layers 104.
- the power source 118 also is coupled to the reference layer structure 106 through electrode 110.
- the electrode 110 may be coupled to a surface of the reference layer structure 106 that is not in contact with the intermediate layers 104.
- the power source 118 provides power
- an electrical current is generated through the MTJ 101 because of the tunnel magneto-resistance (TMR) effect, where electrons tunnel between the free layer structure 102 and the reference layer structure 106 through the one or more intermediate layers 104.
- TMR tunnel magneto-resistance
- anisotropic magneto-resistance and giant magneto-resistance effects can also be used to generate a current through the MTJ 101.
- the one or more intermediate layers 104 may be a thin insulator that separates the free layer structure 102 from the reference layer structure 106.
- the tunneling layers 104 may also include a coupled free layer.
- the one or more tunneling layers 104 may include both a coupled free layer and a coupling-modulating interlayer. Due to the electrons tunneling through the one or more tunneling layers 104, when a current is applied through the MTJ 101 by the power source 118, the current passes through the MTJ 101 from the coupled free layer electrode 108 to the reference layer electrode 110.
- the pressure medium 112 may be capable of damaging the MTJ 101
- the MTJ 101 or a portion of the MTJ 101 that is exposed to the pressure medium 112 is coated with a protective barrier such as silicon dioxide or other protective material that still allows the pressure medium to affect the axis of magnetization of the free layer structure 102.
- the free layer structure 102 may be encapsulated within an inelastic, or relatively inelastic, layer that provides passivation to the MTJ 101 while transmitting the pressure from the pressure medium to the free layer structure 102.
- the MTJ 101 when the current passes through the MTJ 101, the MTJ 101 has a resistance that is dependent on the magnetization direction of the free layer structure 102 in relation to the reference layer structure 106.
- the MTJ 101 when the directions of magnetization for the free layer structure 102 and the reference layer structure 106 are parallel (i.e., oriented in the same direction), the MTJ 101 has a low resistance.
- the free layer structure 102 experiences pressure from the pressure medium 112
- the direction of magnetization changes in the free layer structure 102.
- the resistance also changes. For example, the resistance may increase.
- the current through the MTJ 101 also changes.
- a current detector 114 coupled in series with the MTJ 101 and the power source, detects changes in the current passing through the MTJ 101.
- the current detector 114 may be a current monitor.
- the current detector 114 may be a resistor.
- the current detector 114 provides a signal to a pressure calculation device 116 that calculates the pressure based on the current passing through the MTJ 101.
- the pressure calculation device 116 may be a processor, digital or analog circuitry, or other devices capable of using the detected pressure for a desired means.
- the MTJ 101 is able to be used as a pressure sensing device.
- Figures 2A-2C illustrate different implementations of MTJs such as the MTJ 101 described above in connection with Figure 1 .
- Figure 2A illustrates an MTJ 201a having only a tunnel barrier 203 separating the free layer structure 202 from the reference layer structure 206.
- the free layer structure 202 may be fabricated from one of many different materials.
- the free layer structure 202 may be fabricated from at least one of Ni, Fe, NiFe, FeAl (Alfer), TbDyFe (Terfenol-D), FeGa, TbFe, TbFe 2 , or other materials suitable for providing the desired functionality.
- the reference layer structure 206 can be fabricated using at least one of NiMn, PtMn, IrMn, FeMn, for example, in association with one or more ferromagnets, or other materials suitable for functioning as a reference layer.
- the tunnel barrier 203 may be fabricated from at least one of AlOx, MgO, or other materials suitable for functioning as a tunnel barrier.
- different processes used in fields of thin film technology may be used.
- the materials of the various layers in the MTJ 201a may be fabricated using magnetron sputter deposition, molecular beam epitaxy, pulsed laser deposition, electron beam physical vapor deposition, and photolithography, among other processes.
- the MTJ 201a may exhibit the following exemplary ranges during operation.
- the MTJ 201a may have a range of 80 MPa using Ni for the free layer structure 202 with 1° of angular resolution for the rotation of the direction of magnetization for the free layer structure 202.
- the MTJ 201a may have a range of 35 MPa using NiFe for the free layer structure 202 with 1° of angular resolution for the rotation of the direction of magnetization for the free layer structure 202.
- the MTJ 201a may have a range of 2.6 MPa using TbDyFe for the free layer structure 202 with 1° of angular resolution for the rotation of the direction of magnetization for the free layer structure 202.
- the MTJ 201a may have a range of 1.1 MPa using TbFe for the free layer structure 202 with 1° of angular resolution for the rotation of the direction of magnetization for the free layer structure 202.
- Figure 2B illustrates an MTJ 201b that includes a coupled free layer 205 between a tunnel barrier 203 and a free layer structure 202.
- the coupled free layer 205 is used to allow further control of the magnetization and the spin conduction profile of the magnetoresistance.
- the addition of the coupled free layer 205 permits different angles for the rotation of the axis in the coupled free layer. It may also provide for a more desired magnetoresistance.
- the coupled free layer may be fabricated from ferromagnets such as Ni, Fe, NiFe, CoFe, CoNiFe, among other materials.
- Figure 2C illustrates an MTJ 201c that includes a coupling-modulated interlayer 207 between a coupled free layer 205 and a free layer structure 202.
- the coupling-modulated interlayer 207 allows the separation of magnetization coupling from the magnetoresistance.
- the coupled free layer 205 is chosen to optimize the magnetoresistance
- the coupling-modulated interlayer 207 is used to optimize the spin conduction profile.
- the coupling-modulated interlayer 207 may be fabricated from Cu, Ru, or other suitable materials that permit the desired functionality.
- Figures 3A-3E illustrate different rotational direction configurations for a free layer structure (FL) in relation to the reference (or pinned) layer structure (PL).
- FL free layer structure
- PL reference layer structure
- Figures 3A-3C illustrates a FL where the magnetization direction rotates within the plane of the free layer.
- Figure 3A and 3B are similar to one another, with the exception that the direction of magnetization of the FL rotates in different directions within the same plane.
- Figure 3C illustrates an implementation where the FL and the PL are initially set to a higher resistance, as illustrated by the magnetization directions being in opposite directions and then in response to decreasing pressure, the direction of magnetization of the FL moves such that the resistance decreases.
- Figures 3D-3E illustrate implementations where, the direction of magnetization changes in a plane perpendicular to the plane of the FL and the PL.
- Figure 3D is similar to the embodiment shown in Figure 3C , with the exception that the magnetization changes in a plane perpendicular to the plane of the FL.
- Figure 3E corresponds is similar to the embodiments of either Figure 3A or 3B .
- Figure 4 is a method 400 for fabricating a pressure sensor using an MTJ.
- Method 400 proceeds at 402, where a magnetic tunnel junction is fabricated, where the magnetic tunnel junction includes a free layer structure, a tunnel barrier, and a reference layer structure. Further, the free layer structure is fabricated such that at least one surface will be exposed to a pressure medium.
- Method 400 proceeds at 404, where the free layer structure and reference layer structure are coupled to a voltage source.
- Method 400 proceeds at 406 where a current detector is coupled between the magnetic tunnel junction and the voltage source.
- Method 400 proceeds at 408, where a pressure calculating device is coupled to the current detector. The pressure calculating device uses the current measurements to determine the pressure exerted by the pressure medium on the MTJ.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Hall/Mr Elements (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201562193742P | 2015-07-17 | 2015-07-17 | |
US14/839,301 US10082431B2 (en) | 2015-07-17 | 2015-08-28 | System and methods for magnetic tunnel junction pressure sensors |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3118596A1 true EP3118596A1 (fr) | 2017-01-18 |
Family
ID=56372814
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP16178512.6A Ceased EP3118596A1 (fr) | 2015-07-17 | 2016-07-07 | Système et procédés pour capteurs de pression de jonction de tunnel magnétique |
Country Status (2)
Country | Link |
---|---|
US (1) | US10082431B2 (fr) |
EP (1) | EP3118596A1 (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3623777A1 (fr) * | 2018-09-11 | 2020-03-18 | Honeywell International Inc. | Dispositif de capteur spintronique de chocs mécaniques et de vibrations |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10802087B2 (en) | 2018-09-11 | 2020-10-13 | Honeywell International Inc. | Spintronic accelerometer |
US10942072B2 (en) | 2018-11-20 | 2021-03-09 | International Business Machines Corporation | Nanoscale magnetic tunnel junction arrays for sub-micrometer resolution pressure sensor |
US11226252B2 (en) | 2019-01-07 | 2022-01-18 | International Business Machines Corporation | Multilayered magnetic free layer structure in magnetic tunnel junction arrays for sub-micrometer resolution pressure sensors |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0889521A2 (fr) * | 1997-07-02 | 1999-01-07 | STMicroelectronics, Inc. | Appareil et procédé d'emballage des capteurs d'empreintes digitales à l'état solide |
US20020073785A1 (en) * | 2000-12-20 | 2002-06-20 | Shiva Prakash | Use of multi-layer thin films as stress sensors |
US20140369530A1 (en) * | 2013-06-12 | 2014-12-18 | Kabushiki Kaisha Toshiba | Pressure sensor, acoustic microphone, blood pressure sensor, and touch panel |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5165284A (en) | 1990-04-05 | 1992-11-24 | Matsushita Electric Industrial Co., Ltd. | Pressure sensor utilizing a magnetostriction effect |
US6756237B2 (en) * | 2002-03-25 | 2004-06-29 | Brown University Research Foundation | Reduction of noise, and optimization of magnetic field sensitivity and electrical properties in magnetic tunnel junction devices |
DE10214946B4 (de) * | 2002-04-04 | 2006-01-19 | "Stiftung Caesar" (Center Of Advanced European Studies And Research) | TMR-Sensor |
US7541804B2 (en) | 2005-07-29 | 2009-06-02 | Everspin Technologies, Inc. | Magnetic tunnel junction sensor |
US7547480B2 (en) | 2005-10-28 | 2009-06-16 | Everspin Technologies, Inc. | Magnetic tunnel junction pressure sensors and methods |
US7902616B2 (en) * | 2008-06-30 | 2011-03-08 | Qimonda Ag | Integrated circuit having a magnetic tunnel junction device and method |
US9171601B2 (en) * | 2009-07-08 | 2015-10-27 | Alexander Mikhailovich Shukh | Scalable magnetic memory cell with reduced write current |
US9093163B2 (en) * | 2010-01-14 | 2015-07-28 | Hitachi, Ltd. | Magnetoresistive device |
US8975891B2 (en) * | 2011-11-04 | 2015-03-10 | Honeywell International Inc. | Apparatus and method for determining in-plane magnetic field components of a magnetic field using a single magnetoresistive sensor |
JP5701807B2 (ja) | 2012-03-29 | 2015-04-15 | 株式会社東芝 | 圧力センサ及びマイクロフォン |
-
2015
- 2015-08-28 US US14/839,301 patent/US10082431B2/en active Active
-
2016
- 2016-07-07 EP EP16178512.6A patent/EP3118596A1/fr not_active Ceased
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0889521A2 (fr) * | 1997-07-02 | 1999-01-07 | STMicroelectronics, Inc. | Appareil et procédé d'emballage des capteurs d'empreintes digitales à l'état solide |
US20020073785A1 (en) * | 2000-12-20 | 2002-06-20 | Shiva Prakash | Use of multi-layer thin films as stress sensors |
US20140369530A1 (en) * | 2013-06-12 | 2014-12-18 | Kabushiki Kaisha Toshiba | Pressure sensor, acoustic microphone, blood pressure sensor, and touch panel |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP3623777A1 (fr) * | 2018-09-11 | 2020-03-18 | Honeywell International Inc. | Dispositif de capteur spintronique de chocs mécaniques et de vibrations |
US10871529B2 (en) | 2018-09-11 | 2020-12-22 | Honeywell International Inc. | Spintronic mechanical shock and vibration sensor device |
Also Published As
Publication number | Publication date |
---|---|
US10082431B2 (en) | 2018-09-25 |
US20170016784A1 (en) | 2017-01-19 |
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